NAME

Audio::Chromaprint - Interface to the Chromaprint library

VERSION

version 0.002

SYNOPSIS

use Audio::Chromaprint;
use Path::Tiny qw< path >;

my $cp = Audio::Chromaprint->new();

$cp->start( 44_100, 1 ); # sample rate (Hz), 1 audio stream
$cp->feed( path('file.wav')->slurp_raw );
$cp->finish;

say "Fingerprint hash: ", $cp->get_fingerprint_hash;

DESCRIPTION

Chromaprint is the core component of the AcoustID project. It's a client-side library that implements a custom algorithm for extracting fingerprints from any audio source.

You can read more about Chromaprint on its website.

This binding was done against 1.4.3. While it should work for newer versions, please let us know if you are experiencing issues with newer versions.

ATTRIBUTES

algorithm

Integer representing the Chromaprint algorithm.

Acceptable values:

• 1
• 2
• 3
• 4

The default is 2. (This is the default in Chromaprint.)

silence_threshold

An integer representing the silence threshold.

Accepting a number between 0 and 32,767 (without a comma).

METHODS

new

my $chromaprint = Audio::Chromaprint->new(
    'algorithm'         => 1,     # optional, default is 2
    'silence_threshold' => 1_000, # optional,
);

start

$chromaprint->start( $sample_rate, $num_streams );

Start the computation of a fingerprint with a new audio stream.

First argument is the sample rate (in integer) of the audio stream (in Hz).

Second argument is number of channels in the audio stream (1 or 2).

set_option

$chromaprint->set_option( $key => $value );

Setting an option to Chromaprint.

In version 1.4.3 only the silence_threshold is available, which we also expose during instantiation under new.

get_version

my $version = $chromaprint->get_version();

Returns a string representing the version.

feed

$chromaprint->feed($data);

Feed data to Chromaprint to analyze. The size definitions are handled in the module, so you only send the data, no need for more.

You can use Path::Tiny to do this easily using the slurp_raw:

use Path::Tiny qw< path >;
my $file = path('some_file.wav');
my $data = $file->slurp_raw();

$chromaprint->feed($data);

finish

$chromaprint->finish();

Process any remaining buffered audio data.

This has to be run before you can get the fingerprints.

get_fingerprint

my $fingerprint = $chromaprint->get_fingerprint();

Provides a compressed string representing the fingerprint of the file. You might prefer using get_fingerprint_hash.

get_fingerprint_hash

my $fingerprint_hash = $chromaprint->get_fingerprint_hash();

Provides a hash string, representing the fingerprint for the file.

get_raw_fingerprint

my $raw_fingerprint = $chromaprint->get_raw_fingerprint();

Return the calculated fingerprint as an array of 32-bit integers.

get_raw_fingerprint_size

my $fingerprint_size = $chromaprint->get_fingerprint_size();

Return the length of the current raw fingerprint.

clear_fingerprint

$chromaprint->clear_fingerprint();

Clear the current fingerprint, but allow more data to be processed.

get_num_channels

my $num_of_channels = $chromaprint->get_num_channels();

Get the number of channels that is internally used for fingerprinting.

get_sample_rate

my $sample_rate = $chromaprint->get_sample_rate();

Get the sampling rate that is internally used for fingerprinting.

get_item_duration

my $item_duration = $chromaprint->get_item_duration();

Get the duration of one item in the raw fingerprint in samples.

get_item_duration_ms

my $item_duration_ms = $chromaprint->get_item_duration_ms();

Get the duration of one item in the raw fingerprint in milliseconds.

get_delay

my $delay = $chromaprint->get_delay();

Get the duration of internal buffers that the fingerprinting algorithm uses.

get_delay_ms

my $delay_ms = $chromaprint->get_delay_ms();

Get the duration of internal buffers that the fingerprinting algorithm uses.

UNSUPPORTED METHODS

We do not yet support the following methods.

• encode_fingerprint
• decode_fingerprint
• hash_fingerprint

AUTHORS

• Sawyer X xsawyerx@cpan.org
• Graham Ollis plicease@cpan.org

COPYRIGHT AND LICENSE

This software is Copyright (c) 2019 by Sawyer X.

This is free software, licensed under:

The MIT (X11) License